Multiple unit tube



Jaim24, 1933. ogwg I 1,895,255

MULTIPLE UNIT TUBE Filed April 29, 1927 INVENTOR SEGMUND .LUEWE YawATTORNEY Patented Jan.- 24, 1933 UNITED STATES A E T FF E;

SIEGMUND LOEWE, OF BERLIN, EEIEEENAU, GERMANY, As sIeNoE T0 EAnIoGORPORA- 1i TION OF AMERICA, A CORPORATION or DELAWARE '1 MULTIPLE UNTUBE Application filed April 29, 1927, Serial No. 187,684, and inGermany ,l'uly 19, 1926. v

The present invention discloses ways and means whereby improvements inmultipleunit tubes for line connection can be carried into practice. Theso-called multiple-unit tubes contain within a joint vacuous spaceseveral amplifier systems together with the requisite coupling elements,the latter consisting most generally of high-ohmic resistances andblocking condensers.

The subject-matter of the present invention is a multiple-unit tubespecially designed and adapted for direct connection with a supplycircuit or network. The chief feature of the same resides in the factthat the filaments of all of the systems contained inside themultiple-unit tube are connected in series, for the purpose of beingable to obtain the comparatively high negative biasing potential required for the last grid directly in the tube itself, so that no distantseal and lead-in is required for the last grid. If'the potential dropacross the series-connected filaments 1s not yet suflicient, then aseparate series resistance is disposed in series with the filaments,also in the tube itself. Connection with the last grid is then also madeinside the tube, to be more precise, with this series resistance.

A tube having this construction is illustrated in Figure 1. g

The joint vacuous space 1 contains three amplifier systems. Thefilaments are designated by 2, 3 and 4. According to this invention, allof these cathodes are connected in series, with the result that onlytwoleadouts are required, an additional resistance being connected inseries with the first filament 2. 5, 6 and 7 are the grids of the threestages, and 8, 9 and 10 their plates. 11 and 12 are plate resistances,13, 14 grid leaks, 15, 16 coupling condensers, 17 the lead to the firstgrid. The current-supply lead to the first two plates is denoted by 18.l

The biasing potentials are obtained in the following manner: In the caseof the second grid, the leak resistance 13 is connected with thenegative filament pole of the tube next below. The grid of the thirdtube which ordinarily is of the loud speaker terminalstage type, andwhich possesses a high inverse amplification factor and therefore ahigh. biasing potential (from 6. to 15 volts), of the filamentscombinedly involve at least from 10 "to 15 volts potential drop,are'likewise connected with the negative 'filament pole ofcathode 2. Ifthis is not thecase, connection ismadewith the distinct seriesresistance 19. In this manner, a three stage tube is provided with onlyfive connections,

that is, only one connection more than the ordinary tube. At the sametime, this tube is particularly suited for network-connection devicesand hot-cathode rectifiers with which it is comparatively easy to obtainhigh potentials, but only large currents with difiiculty. The seriesarrangement of the filaments therefore makes the tube especially Qsuited for use with network. connection means, while making dispensablea separate lead-in for the grid-leak of the last stage.

I claim as my invention:

1. A multiple-unit tube having a plurals ity of stages, eachstagecomprising a filament, control electrode, and anode, the filamentsof said stages being connected in series 7 and a connection within thetube between the grid of one of the stages and the filament of thepreceding stage for biasing the said grid.

2. A three-stage multiple-unit tube having a plurality of stages, eachstage comprising afilament, control electrode, and anode, the filamentsof said stages being connected in series, a connection between the gridof the second stage and the negative pole of the filament of the firststage for biasing the grid of the second stage, and a connection ,7

betweenthe grid of the last stage and an impedance within the tube inseries with the leadto the said negative pole.

3. A multi stage amplifier tube unit having a plurality of multipleelectrode systems, each system comprising a filament, control electrode,and anode, the filaments of said systems being connected in series;means within the tube for obtaining a biasing potential for one of saidsystems at the negative pole of the filament of a precedingjsystern; andother means for taking the blasing potential for the end system oil atthe negative filament pole of a preceding system.

4. In a multi stage amplifier tube, a plurality of stages, each stagecomprising a cathode, a control electrode, and an anode, the cathodes ofall the stages being connected in series; a resistance in series withthe cathode of the first stage; and connections within the tube fromsaid resistance to the control electrodes of the intermediate andendstages of said amplifier, for supplying biasing potentials thereto.7;

5. A three stage amplifier tube, each stage comprising'a cathode,control electrode, and

anode; a resistance in series with the cathode of the first stage; aconnection between one point on said resistance and the control elec-'trode of the second stage of said amplifier for supplying a biasingpotential thereto; and

another connection from another point on said resistance to the controlelectrode, ofthe end stage of said amplifier for supplying a biasingpotential thereto. i; SIEGMUND LOEWE.

